1. Field of the Invention
This present invention is directed to blowout preventers, to locking mechanisms for them, and methods of their use.
2. Description of Related Art
The prior art discloses a wide variety of blowout preventers and locking mechanisms for blowout preventers.
Typical blowout preventers have selectively actuatable rams with movement systems for selectively moving the rams from open to closed positions. The prior art discloses a wide variety of locking mechanisms for locking the rams in a closed position. Rams include pipe rams (to contact, engage, and encompass pipe and/or tools to seal a wellbore), shear rams (to contact and physically shear a pipe or tool in a wellbore) which are usually positioned opposite each other on either side of a main body; and variable bore rams (to contact, encompass, and engage tubulars or pipe of multiple sizes and/or tools or apparatuses to seal a wellbore).
Blowout preventers are disclosed in many U.S. patents, including, but not limited to, U.S. Pat. Nos. 3,946,806; 4,043,389; 4,313,496; 4,132,267, 4,558,842; 4,969,390; 4,492,359; 4,504,037; 2,752,119; 3,272,222; 3,744,749; 4,253,638; 4,523,639; 5,025,708; 5,056,418; 5,400,857; 5,575,452; 5,655,745; and 5,918,851 and in the prior art references cited in these patents.
There has long been a need, recognized by the present inventor for a blowout preventer with an effective and adjustable shaft locking apparatus; and in certain aspects, such an apparatus which is automatic.